Conventional methods for controlling display devices comprising a screen whereon the information is to be projected generally envisage a synchronous operating mode wherein the display of images in the form of a pixel array is performed substantially periodically. The display period determines the dynamic display range of the device, and is most often the result of a compromise between the hardware limitations of the devices (including those relating to the computing capabilities thereof), and the need to attain a temporal resolution providing maximum visual comfort.
This display period further corresponds to the period at which the display of the pixels of the array is refreshed, given that the display is controlled so as to display all the pixels of the array simultaneously or quasi-simultaneously. For example, the display of a video frame will be performed in certain systems by periodically displaying a sequence of sub-frames (so-called “even” sub-frames, corresponding to a subarray comprising the rows of even sequential number of the pixel array corresponding to the frame, and so-called “odd” sub-frames, corresponding to a subarray comprising the rows of odd sequential number of the pixel array corresponding to the frame), such that the set of pixels of each sub-frame will be displayed (or lit) periodically, the sub-frames being displayed in alternation at a frequency twice as high as the display frequency of the frames.
The temporal resolution that can be attained notably for systems intended for the general public is thus limited in that the display methods used envisage a quasi-simultaneous display of a large number of pixels of the corresponding pixel array, on the display screen, at a frequency in turn limited by the processing capabilities of these systems.
Moreover, it would appear that it is quasi-impossible to transpose conventional display methods in the context of the control of vision aid devices. Indeed, implants or optogenetic treatment methods require luminous stimulation signals of much higher intensity than that of ambient light. A vision aid implant placed under the eye, typically comprising an electrode around which one to three photodiodes are arranged, will only function effectively if these photodiodes receive light seven times more powerful than that of ambient light, such that the photodiodes can emit a stimulus. Similarly, current optogenetic treatments are only fully effective if the treated eye receives luminous signals having a specific wavelength and a luminous intensity ranging from two to seven times that of ambient light. The luminous powers required are thus so high that the use of conventional display methods, at these power levels, would cause lesions on users' visual organs.
As such, there is a need for display methods, not having the drawbacks of the conventional methods described above. In particular, a first need is that of providing display control methods suitable for attaining higher display resolutions than those resulting from the compromises made with conventional systems. A further need is that of providing display control methods which can be used for applications in the vision aid field.